Thumb Screw
Screws · knurled screw · hand screw · wing screw
Definition: A thumb screw has a knurled, wing, or lobed head that is tightened and loosened by hand — no tool required.
Anatomy & Schematic
■ Head■ Shank■ Threads■ Point
Governing standards: Manufacturer specified (no universal standard)
Common Sizes
| Inch | Metric | Head width | Head height |
|---|---|---|---|
| #6-32 | M3.5 | — | 1/4 to 1 long |
| #8-32 | M4 | — | 1/4 to 1-1/2 long |
| 1/4-20 | M6 | — | 3/8 to 2 long |
Representative sizes. Full dimensional data lives in the standards listed below.
Grades & Strength
| Grade | Material | Tensile (psi) | Marking |
|---|---|---|---|
| Steel / stainless | steel | — | None |
| Brass / nylon | varies | — | None |
Materials
- Zinc-plated steel
- Stainless steel
- Brass
- Nylon
Pros & Cons
Pros
- Tool-free adjustment
- Quick release
- Cheap
Cons
- Low torque — hand strength only
- Can loosen under vibration
- Knurling wears with use
Typical Uses
- Electronics covers
- Camera and optical mounts
- Jigs and fixtures
- Tool-free panels
Alternatives & Related
- Wing Nut — Hand-tightened from the nut side
- Machine Screw — When you need a driver for higher torque
Where to Buy
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FAQ
What is a thumb screw used for?
Panels and covers that need frequent hand access without tools — electronics, cameras, jigs, and fixtures.
Thumb screw vs wing screw?
Both are hand-turned; a thumb screw has a knurled or lobed head, a wing screw has two protruding wings for more leverage.